This invention relates to the art of containers, particularly paperboard containers of the type commonly employed for the packaging and storage of liquid foodstuffs, such as milk, orange juice, or the like. The invention relates more specifically to an apparatus for prebreaking the bottom of a container, such as the common gable-top container often employed for the packaging of such foodstuffs.
U.S. Pat. No. 3,412,922 of Nov. 26, 1968, issued to Miller et al discloses a container formed from a single blank of paperboard or the like, the paperboard usually being coated on both sides with a thermoplastic resin to assist in heat sealing during assembly of the container bottom and top and also to seal the paperboard against liquid seepage. The Miller patent discloses a specific bottom construction wherein one flap of two opposed pairs of bottom extension flaps of the blank is provided with a tab. The tab is initially formed by cutting the blank at one of the extension flaps which forms the bottom of the container when the blank is set up and assembled. During formation of the container bottom from the bottom extension flaps, the tab is folded about its fold line or zone of attachment to the bottom flap from which it is formed and is then folded or bent back upon that flap. The purpose of this fold tab construction is to improve the sealing properties of the container by eliminating contact of the container liquid contents with any raw paperboard edges in the carton bottom.
Automatic packing machinery employed for prebreaking the bottom of a container formed from a single paperboard blank is well known. By way of example only, one such apparatus is shown in U.S. Pat. No. 3,593,625 of July 20, 1971, issued to Garrett et al.